I have a set of regions and would like to quantify the degree to which the boundary of these regions are situated on/near rivers. I have turned the regions from polygons to polylines in arcgis 10.1 ...

I have a raster file with pixel size 30 x 30. At the upper border there is half row with "no data" pixels. I want to use the mode function to replace them. I have only thought r.neighbors (from grass) ...

I would like to split areas on a map of north germany between four community centers to split the responsibility for the whole map between these 4 areas.
Is there an online tool where I can draw the ...